The present application is the national stage under 35 U.S.C. 371 of PCT/FR00/00928, filed Apr. 11, 2000.
The invention relates to fasteners for conveyor belt joints, belts and similar products, which comprise hinge elements and are likely to be fixed astride one end of the conveyor belt, the hinge elements being able to be placed between similar hinge elements belonging to a similar fastener at the other end of the conveyor belt, the two fasteners being linked by a linking and articulation pin passing alternately in a hinge element belonging to one of the two fasteners and in a hinge element belonging to the other of the two fasteners, and so on.
The fasteners of this general type can be linked to a conveyor belt end by various known means such as rivets, brads, twin point staples, nut and screw systems. Certain fasteners can be linked directly, without using separate fixation organs, thanks to the claws which are part of the fastener, which are attached in the thickness of the conveyor belt when the fastener is tightened on one end of the conveyor belt.
Document DE-A-832 366 shows fasteners such as these in FIGS. 1, 2, 3 and 4 (in particular claws 10, 11, 12, 13, FIG. 3 and claws 14, 15, 16, 17, FIG. 4).
Document U.S. Pat. No. 4,344,209 also shows claws 106, in FIG. 2.
A document FR-A-2 163 833 now in the public domain shows such fasteners, comprising curved claws which, once the fastener is set in place, cross through the conveyor belt completely and are bent back underneath it, and not under the lower part of the fastener (see p. 4114 to 4128).
However, since a gap between the two branches of the fastener is not excluded with such an arrangement, this patent envisaged using, in combination with the claws included in the fastener, classical twin point staples, whose aim is to ensure that during operation of the conveyor belt the two parts of the fastener forming the fixation plates do not separate in the case where the claws, in the way they are fitted, are not able to prevent such a separation.
Thus the aim of the present invention is to propose a conveyor belt fastener, whose fixation is ensured by claws which are part of the fastener itself, but not calling on, in combination, separate classical means of fixation, such as clamps, rivets, nut and screw systems, and not requiring for its fixation any previous piercing of holes in the end of the conveyor belt, as is the case, for example, for rivets which are often used.
Another aim of the invention is to propose a fastener as mentioned above, not comprising, once fixed on one end of the conveyor belt, any asperity beyond the bounds of the external faces of the fixation plates, which could be caught by a scraper like those used in many industries using conveyor belts.
This problem is solved by means of a fastener for conveyor belt joints comprising an upper fixation plate and a lower fixation plate, the two plates being linked along one of their edges by U-shaped hinge elements, leaving spaces between them for embedding similar hinge elements belonging to another similar fastener, a pin for linking and articulation linking being able to be introduced into the embedded hinge elements to produce the articulated fastener link, said fastener being provided with claws which are part of the upper fixation plate and are oriented towards the lower fixation plate, presenting a curve, or curves whose concavity is preferably oriented towards the hinge elements, characterised in that the lower plates comprise ports on their side opposite to the hinge elements, said ports being constituted of a small bar of the same material as that constituting the lower plate, oriented parallel to the edge of the lower plate situated opposite to the hinge elements and raised relative to the general plane of the lower plate, a shearing being practised on each side of the small bar, the edge of the lower plate situated opposite the hinge elements being raised and presenting a curved profile, the claws of the upper plate, the ports and the raised edge of the lower plate being arranged respectively in such a way that when the fastener, initially open, is closed, the points of the claws come up against the raised edge with a curved profile in its upper part, on the side of the raised edge with curved profile oriented towards the hinge elements of the fastener.